Touch panels for receiving inputs, for example, from a person's touch, are in widespread use. A convenient input/display device can be obtained by, for example, providing a liquid crystal display device etc. with a touch input function.
For example, there is a type of touch panel system in which a change in electric capacitance when the input surface is touched is sensed. In the system, the response speed is slow due to the problem of the time constant. Therefore, if sensing within a prescribed time is necessary, the arranged density of sensors can be reduced, and consequently the resolution cannot be sufficiently improved.